View is not being resolved with Toolbar ItemsSource

Question

It doesn't seem like the Caliburn Micro framework is retrieving my SinglePaintToolbarView when it is binded as a list of buttons in the toolbar of the ShellView. I would like the buttons to just display their text content when they are added to the toolbar. But, instead I'm getting this:

There doesn't appear to be any clickable buttons in the toolbar. I know my plugins are being loaded successfully, because I was able to bind one of the plugins in the list as a ContentControl and the view appeared. It just doesn't seem to work when I try to bind a list of the plugins in a toolbar.

Here is what I have:

ShellView.xaml

<UserControl x:Class="Starbolt.Views.ShellView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
    <Grid>
        <ToolBarTray>
            <ToolBar ItemsSource="{Binding Path=ToolbarPlugins}"/>
        </ToolBarTray>
    </Grid>
</UserControl>

ShellViewModel.cs

[Export(typeof(IShell))]
public class ShellViewModel : PropertyChangedBase, IShell
{

    [ImportMany(typeof(IToolbarPlugin))]
    private IEnumerable<IToolbarPlugin> _toolbarPlugins = null;

    public IEnumerable<IToolbarPlugin> ToolbarPlugins { get { return _toolbarPlugins; } }
}

SinglePaintToolbarView.xaml

<UserControl x:Class="Starbolt.Plugin.SinglePaintTool.Views.SinglePaintToolView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="128" d:DesignWidth="32">
    <Button Name="btnSinglePaintTool" Content="Single Paint Tool" Width="128" Height="32"/>
</UserControl>

SinglePaintToolViewModel.cs

[Export(typeof(IToolbarPlugin))]
public class SinglePaintToolViewModel : IToolbarPlugin
{

}

Answer 1

Basically, your design seems to be working. If you replace

<ToolBarTray>
    <ToolBar x:Name="ToolbarPlugins"/>
</ToolBarTray>

(note that you do not need to bind the ItemsSource explicitly, you can just as well use the Caliburn Micro property name conventions) with the following:

<ListBox x:Name="ToolbarPlugins"/>

the SinglePaintToolView button is displayed as intended.

I suspect that the problem is with the ToolBar ControlTemplate, which most certainly restricts the toolbar items layout more than what for example a ListBox ControlTemplate does.

So my guess is that if you really want to use the ToolBar control to display your IToolbarPlugin views, you will probably have to design a dedicated ToolBar control template in your project.

Alternatively, you could implement a toolbar replacement using e.g. ListBox. This could be a start:

<ListBox x:Name="ToolbarPlugins">
    <ListBox.ItemsPanel>
        <ItemsPanelTemplate>
            <StackPanel Orientation="Horizontal" />
        </ItemsPanelTemplate>
    </ListBox.ItemsPanel>
</ListBox>